public class BookSystem {
    public static void main (String [] args) {
        String [] bookIds = {"B001", "B002", "B003", "B004", "B005"};
        String [] bookNames = {"Java 编程基础", "数据结构与算法", "Python 入门", "数据库原理", "计算机网络"};
        boolean [] isBorrowed = {true, false, true, false, false}; //true: 已借出，false: 未借出
        System.out.println ("当前可借阅的图书：");
        int availableCount = 0;
        for (int i = 0; i < bookIds.length; i++) {
            if (!isBorrowed [i]) { // 未借出
                System.out.println (bookIds [i] + ":" + bookNames [i]);
                availableCount++;
            }
        }
        System.out.println ("可借阅图书总数：" + availableCount);
        String returnBookId = "B001";
        for (int i = 0; i < bookIds.length; i++) {
            if (bookIds [i].equals (returnBookId)) {
                isBorrowed [i] = false;
                System.out.println ("\n" + returnBookId + "已归还");
                break;
            }
        }
        availableCount = 0;
        for (boolean borrowed : isBorrowed) {
            if (!borrowed) availableCount++;
            System.out.println ("归还后可借阅图书总数：" + availableCount);
        }
    }
}
